I spoke to Jillian and she was amazing! Very atten...

I spoke to Jillian and she was amazing! Very attentive/nice and willing to hear me out on what I wanted. We had come to an agreed price for the amount due at signing and my monthly rate.
But.. after everything was set and done and I was called to be informed that my credit was great (above 700) and the loan was approved. Keith (finance manager) tells me last minute (when I m already in his office) that my rate was going up and I had to include a couple hundred more for the down payment. When I asked why? He said that it was because I got accepted as a tier 2 and the extra money was for the plates.
We negotiated the price before hand. My credit was great thus I know it was tier 1. The original down payment already included the plates according to what they told me earlier on and what was typed up on the buyers contract but of course he insisted otherwise. I also had my friend on the phone while I spoke to Keith who worked at a dealership in the past and he informed me it was just fluff.
I believe this was unethical. If we had already came to an agreed price, at least tell me before hand that you intended on raising my rate (could ve told me over the phone as well) and not had me in your office to tell me last minute.
I decided to go with the purchase because it wasn t much more money but the issue here is the principle. It was unethical, dishonest behavior on his behalf and deceitful.